IMHO
For me it is a question of reliability. In a self defense perspective. When you need a weapon you want the one most likely to work. From the info I have gathered Glocks are less likely to jam. I have had several jams in 1911 styled guns and find there reliability to be temperamental at times, but find Glock jams to be very very rare and it's reliability to be top shelf. Now I don't doubt that if you buy a "gun snobs" $1000.00 1911 and keep it very clean then it would have less of a jam problem.
Doc
The self defense situation is a very valid point, however, I can not imagine someone having a firearm for self defense that is not clean, that just does not make sense. Most self defense situations are going to involve less than 10 rounds (depends upon the "empty the mag theory) and 10 rounds won't leave a lot of dirt behind.
Have you ever noticed how the debate/argument flows, the glock fan boys always talk about all the jams and problems they have had with other guns but have never had a problem with a glock?
The fact is, all guns can and do jam, many guns are indeed very reliable and glock is by no means the only choice or even the best choice, it is simply a good choice.
As you decided to target the 1911 and refrenced reliability and self defence, I opted to include a low end and a high end 1911 video along with a glock video to make it a little more clear for those reading along.
Tarus 1911 900 rounds in ten minutes a few FTF
http://www.youtube.com/watch?v=Gx7HYgTWAsg&feature=player_embedded
Todd Jarret putting 1,000 rounds through a para 1911 in ten minutes
http://www.youtube.com/watch?v=lqtA84eBmPQ
Glock 1000 round test, this is the second half only, a few FTF guid rod fell out of it.
http://www.youtube.com/watch?v=CyZxQfIBXDc&feature=related
Now notice both 1911 completed the task in tact, the glock did not. It melted and the guide rod recoil spring indeed did fall out of the gun. While I am sure it would have been the operators fault had the slide busted him in the forehead, since it did not, that is only speculation.
When you look at a 1911, the variables are so large they simply can not be compared, from a mil-spec gun to a pistol that will shoot 1" groups at 25 yards, if you tighten any firearm up to make it very accurate, you loose reliability unless cleaned, it is simply a matter of no place for the dirt to go but in the way. Glocks are out of the box a loose weapon with a lot of space for dirt to build up as are XD's and Mil-spec 1911 pistols.
Even more telling Doc, I have seen several photos of you carrying weapons but none of those photos have I noticed your "weapon of choice" for self defense. Not going personal there, just noting the facts.